319 lines
		
	
	
		
			9.8 KiB
		
	
	
	
		
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			319 lines
		
	
	
		
			9.8 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
| // Copyright David Abrahams 2002.
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| // Distributed under the Boost Software License, Version 1.0. (See
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| // accompanying file LICENSE_1_0.txt or copy at
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| // http://www.boost.org/LICENSE_1_0.txt)
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| #ifndef DATA_MEMBERS_DWA2002328_HPP
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| # define DATA_MEMBERS_DWA2002328_HPP
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| 
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| # include <boost/python/detail/prefix.hpp>
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| 
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| # include <boost/python/handle.hpp>
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| 
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| # include <boost/python/return_value_policy.hpp>
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| # include <boost/python/return_by_value.hpp>
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| # include <boost/python/return_internal_reference.hpp>
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| # include <boost/python/make_function.hpp>
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| 
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| # include <boost/python/converter/builtin_converters.hpp>
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| 
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| # include <boost/python/detail/indirect_traits.hpp>
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| # include <boost/python/detail/not_specified.hpp>
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| # include <boost/python/detail/value_arg.hpp>
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| 
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| # include <boost/type_traits/add_const.hpp>
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| # include <boost/type_traits/add_reference.hpp>
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| # include <boost/type_traits/is_member_pointer.hpp>
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| 
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| # if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
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| #  include <boost/type_traits/remove_cv.hpp>
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| # endif 
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| 
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| # include <boost/mpl/eval_if.hpp>
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| # include <boost/mpl/if.hpp>
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| # include <boost/mpl/vector/vector10.hpp>
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| 
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| # include <boost/detail/workaround.hpp>
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| 
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| namespace boost { namespace python { 
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| 
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| //
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| // This file defines the make_getter and make_setter function
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| // families, which are responsible for turning pointers, references,
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| // and pointers-to-data-members into callable Python objects which
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| // can be used for attribute access on wrapped classes.
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| //
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| 
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| namespace detail
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| {
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| 
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|   // A small function object which handles the getting and setting of
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|   // data members.
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|   template <class Data, class Class>
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|   struct member
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|   {
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|    public:      
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|       member(Data Class::*which) : m_which(which) {}
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|       
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|       Data& operator()(Class& c) const
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|       {
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|           return c.*m_which;
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|       }
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| 
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|       void operator()(Class& c, typename value_arg<Data>::type d) const
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|       {
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|           c.*m_which = d;
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|       }
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|    private:
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|       Data Class::*m_which;
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|   };
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| 
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|   // A small function object which handles the getting and setting of
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|   // non-member objects.
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|   template <class Data>
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|   struct datum
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|   {
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|    public:      
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|       datum(Data *which) : m_which(which) {}
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|       
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|       Data& operator()() const
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|       {
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|           return *m_which;
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|       }
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| 
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|       void operator()(typename value_arg<Data>::type d) const
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|       {
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|           *m_which = d;
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|       }
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|    private:
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|       Data *m_which;
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|   };
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|   
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|   //
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|   // Helper metafunction for determining the default CallPolicy to use
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|   // for attribute access.  If T is a [reference to a] class type X
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|   // whose conversion to python would normally produce a new copy of X
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|   // in a wrapped X class instance (as opposed to types such as
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|   // std::string, which are converted to native Python types, and
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|   // smart pointer types which produce a wrapped class instance of the
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|   // pointee type), to-python conversions will attempt to produce an
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|   // object which refers to the original C++ object, rather than a
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|   // copy.  See default_member_getter_policy for rationale.
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|   // 
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|   template <class T>
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|   struct default_getter_by_ref
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|       : mpl::and_<
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|           mpl::bool_<
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|               to_python_value<
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|                   typename value_arg<T>::type
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|               >::uses_registry
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|           >
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|         , indirect_traits::is_reference_to_class<
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|               typename value_arg<T>::type
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|           >
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|        >
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|   {
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|   };
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| 
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|   // Metafunction computing the default CallPolicy to use for reading
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|   // data members
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|   //
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|   // If it's a regular class type (not an object manager or other
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|   // type for which we have to_python specializations, use
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|   // return_internal_reference so that we can do things like
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|   //    x.y.z =  1
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|   // and get the right result.
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|   template <class T>
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|   struct default_member_getter_policy
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|     : mpl::if_<
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|           default_getter_by_ref<T>
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|         , return_internal_reference<>
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|         , return_value_policy<return_by_value>
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|       >
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|   {};
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| 
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|   // Metafunction computing the default CallPolicy to use for reading
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|   // non-member data.
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|   template <class T>
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|   struct default_datum_getter_policy
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|     : mpl::if_<
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|           default_getter_by_ref<T>
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|         , return_value_policy<reference_existing_object>
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|         , return_value_policy<return_by_value>
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|       >
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|   {};
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| 
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|   //
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|   // make_getter helper function family -- These helpers to
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|   // boost::python::make_getter are used to dispatch behavior.  The
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|   // third argument is a workaround for a CWPro8 partial ordering bug
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|   // with pointers to data members.  It should be convertible to
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|   // mpl::true_ iff the first argument is a pointer-to-member, and
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|   // mpl::false_ otherwise.  The fourth argument is for compilers
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|   // which don't support partial ordering at all and should always be
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|   // passed 0L.
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|   //
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| 
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| #if BOOST_WORKAROUND(__EDG_VERSION__, <= 238)
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|   template <class D, class P>
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|   inline object make_getter(D& d, P& p, mpl::false_, ...);
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| #endif
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| 
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|   // Handle non-member pointers with policies
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|   template <class D, class Policies>
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|   inline object make_getter(D* d, Policies const& policies, mpl::false_, int)
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|   {
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|       return python::make_function(
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|           detail::datum<D>(d), policies, mpl::vector1<D&>()
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|       );
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|   }
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|   
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|   // Handle non-member pointers without policies
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|   template <class D>
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|   inline object make_getter(D* d, not_specified, mpl::false_, long)
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|   {
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|       typedef typename default_datum_getter_policy<D>::type policies;
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|       return detail::make_getter(d, policies(), mpl::false_(), 0);
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|   }
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| 
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|   // Handle pointers-to-members with policies
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|   template <class C, class D, class Policies>
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|   inline object make_getter(D C::*pm, Policies const& policies, mpl::true_, int)
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|   {
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| #if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
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|       typedef typename remove_cv<C>::type Class;
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| #else
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|       typedef C Class;
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| #endif 
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|       return python::make_function(
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|           detail::member<D,Class>(pm)
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|         , policies
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|         , mpl::vector2<D&,Class&>()
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|       );
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|   }
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|       
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|   // Handle pointers-to-members without policies
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|   template <class C, class D>
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|   inline object make_getter(D C::*pm, not_specified, mpl::true_, long)
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|   {
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|       typedef typename default_member_getter_policy<D>::type policies;
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|       return detail::make_getter(pm, policies(), mpl::true_(), 0);
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|   }
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| 
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|   // Handle references
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|   template <class D, class P>
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|   inline object make_getter(D& d, P& p, mpl::false_, ...)
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|   {
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|       // Just dispatch to the handler for pointer types.
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|       return detail::make_getter(&d, p, mpl::false_(), 0L);
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|   }
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| 
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|   //
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|   // make_setter helper function family -- These helpers to
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|   // boost::python::make_setter are used to dispatch behavior.  The
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|   // third argument is for compilers which don't support partial
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|   // ordering at all and should always be passed 0.
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|   //
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| 
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|   
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|   // Handle non-member pointers
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|   template <class D, class Policies>
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|   inline object make_setter(D* p, Policies const& policies, mpl::false_, int)
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|   {
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|       return python::make_function(
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|           detail::datum<D>(p), policies, mpl::vector2<void,D const&>()
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|       );
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|   }
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| 
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|   // Handle pointers-to-members
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|   template <class C, class D, class Policies>
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|   inline object make_setter(D C::*pm, Policies const& policies, mpl::true_, int)
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|   {
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|       return python::make_function(
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|           detail::member<D,C>(pm)
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|         , policies
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|         , mpl::vector3<void, C&, D const&>()
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|       );
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|   }
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| 
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|   // Handle references
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|   template <class D, class Policies>
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|   inline object make_setter(D& x, Policies const& policies, mpl::false_, ...)
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|   {
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|       return detail::make_setter(&x, policies, mpl::false_(), 0L);
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|   }
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| }
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| 
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| //
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| // make_getter function family -- build a callable object which
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| // retrieves data through the first argument and is appropriate for
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| // use as the `get' function in Python properties .  The second,
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| // policies argument, is optional.  We need both D& and D const&
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| // overloads in order be able to handle rvalues.
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| //
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| template <class D, class Policies>
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| inline object make_getter(D& d, Policies const& policies)
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| {
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|     return detail::make_getter(d, policies, is_member_pointer<D>(), 0L);
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| }
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| 
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| template <class D, class Policies>
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| inline object make_getter(D const& d, Policies const& policies)
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| {
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|     return detail::make_getter(d, policies, is_member_pointer<D>(), 0L);
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| }
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| 
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| template <class D>
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| inline object make_getter(D& x)
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| {
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|     detail::not_specified policy
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|         = detail::not_specified(); // suppress a SunPro warning
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|     return detail::make_getter(x, policy, is_member_pointer<D>(), 0L);
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| }
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| 
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| #  if !BOOST_WORKAROUND(__EDG_VERSION__, <= 238)
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| template <class D>
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| inline object make_getter(D const& d)
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| {
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|     detail::not_specified policy
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|         = detail::not_specified(); // Suppress a SunPro warning
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|     return detail::make_getter(d, policy, is_member_pointer<D>(), 0L);
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| }
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| #  endif
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| 
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| //
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| // make_setter function family -- build a callable object which
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| // writes data through the first argument and is appropriate for
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| // use as the `set' function in Python properties .  The second,
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| // policies argument, is optional.  We need both D& and D const&
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| // overloads in order be able to handle rvalues.
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| //
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| template <class D, class Policies>
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| inline object make_setter(D& x, Policies const& policies)
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| {
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|     return detail::make_setter(x, policies, is_member_pointer<D>(), 0);
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| }
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| 
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| template <class D, class Policies>
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| inline object make_setter(D const& x, Policies const& policies)
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| {
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|     return detail::make_setter(x, policies, is_member_pointer<D>(), 0);
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| }
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| 
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| template <class D>
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| inline object make_setter(D& x)
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| {
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|     return detail::make_setter(x, default_call_policies(), is_member_pointer<D>(), 0);
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| }
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| 
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| # if !BOOST_WORKAROUND(__EDG_VERSION__, <= 238)
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| template <class D>
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| inline object make_setter(D const& x)
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| {
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|     return detail::make_setter(x, default_call_policies(), is_member_pointer<D>(), 0);
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| }
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| # endif
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| 
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| }} // namespace boost::python
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| 
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| #endif // DATA_MEMBERS_DWA2002328_HPP
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